A Study on the Buckling of Rectangular Bellows Under Pressure Loads

We have studied the buckling behavior of rectangular bellows under pressure loads. Our final objective is to establish the design guidelines for the rectangular bellows of an experimental fusion reactor, the ITER, the International Thermonuclear Experimental Reactor. Based on the numerical investigation by the FEM, we proposed a simplified method to evaluate the buckling pressure. The evaluation method of the buckling pressure for circular bellows can be found, for example, in the standards of the expansion joint manufacturers association in the U.S.A. (EJMA Standards). For rectangular bellows, however, investigation of the buckling behavior is limited, and EJMA does not provide a method for evaluating the buckling pressure. Therefore, we investigated the buckling behavior of rectangular bellows by the FEM and proposed a simplified evaluation method based on the half-pitch model.